C++ Primer, Fifth Edition

7.2. Access Control and Encapsulation

At this point, we have defined an interface for our class; but nothing forces users to use that interface. Our class is not yet encapsulated—users can reach inside a Sales_data object and meddle with its implementation. In C++ we use access specifiers to enforce encapsulation:

• Members defined after a public specifier are accessible to all parts of the program. The public members define the interface to the class.

• Members defined after a private specifier are accessible to the member functions of the class but are not accessible to code that uses the class. The private sections encapsulate (i.e., hide) ...